A number of horror movies from this era feature mystery and noir elements, such as are found in the Val Lewton films, the Inner Sanctum films with Lon Chaney, and even the Mummy and Dracula films of Universal. Other studios put out similar kinds of films that look attractive to noir fans, like Columbia's "The Soul of a Monster" and this one by 20th Century Fox "The Creeper".
I like and enjoy all these kinds of older horror films very much. Although they were made for popular entertainment, they greatly surpass that category by being of lasting value and artistic worth. More often than not, they transport us into another world. They nicely integrate music, black and white photography, mystery, and story into a satisfying whole. Their genre is horror, but they're not all that horrible or horrifying because they worked within the Code.
"The Creeper" focuses on the character of Janis Wilson who was 18 years old at the time. Her father (Ralph Morgan) is a research doctor who works with Onslow Stevens, and both are assisted by June Vincent. They've returned from a tropical clime where they were experimenting with serums and cats. In nightmarish dreams and flashbacks, we learn how Wilson was traumatized and now fears cats. Morgan and Stevens are having their serious differences concerning continuation of their work. Down the hallway from them is another lab in which John Baragrey and Eduardo Ciannelli work. Baragrey knew and was close to Vincent before her tropical absence. Now he's resuming his relationship but he's also attracted to Wilson. Baragrey and Ciannelli have a black cat called "Creeper" that wanders around.
The story builds mystery in a number of ways. We wonder what Wilson's problem is. We wonder how the cats come into it. We see a large whitish cat's paw on Wilson's windowsill as she sleeps. Then we start to get murders, the first one being Morgan. This short movie is interesting in having Wilson and Vincent go through noticeable changes in the course of the movie.
Review by msroz from the Internet Movie Database.